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Diffstat (limited to 'ext/sqlite/libsqlite/src/random.c')
| -rw-r--r-- | ext/sqlite/libsqlite/src/random.c | 97 | 
1 files changed, 0 insertions, 97 deletions
diff --git a/ext/sqlite/libsqlite/src/random.c b/ext/sqlite/libsqlite/src/random.c deleted file mode 100644 index dd8bdd4c58..0000000000 --- a/ext/sqlite/libsqlite/src/random.c +++ /dev/null @@ -1,97 +0,0 @@ -/* -** 2001 September 15 -** -** The author disclaims copyright to this source code.  In place of -** a legal notice, here is a blessing: -** -**    May you do good and not evil. -**    May you find forgiveness for yourself and forgive others. -**    May you share freely, never taking more than you give. -** -************************************************************************* -** This file contains code to implement a pseudo-random number -** generator (PRNG) for SQLite. -** -** Random numbers are used by some of the database backends in order -** to generate random integer keys for tables or random filenames. -** -** $Id$ -*/ -#include "sqliteInt.h" -#include "os.h" - - -/* -** Get a single 8-bit random value from the RC4 PRNG.  The Mutex -** must be held while executing this routine. -** -** Why not just use a library random generator like lrand48() for this? -** Because the OP_NewRecno opcode in the VDBE depends on having a very -** good source of random numbers.  The lrand48() library function may -** well be good enough.  But maybe not.  Or maybe lrand48() has some -** subtle problems on some systems that could cause problems.  It is hard -** to know.  To minimize the risk of problems due to bad lrand48() -** implementations, SQLite uses this random number generator based -** on RC4, which we know works very well. -*/ -static int randomByte(){ -  unsigned char t; - -  /* All threads share a single random number generator. -  ** This structure is the current state of the generator. -  */ -  static struct { -    unsigned char isInit;          /* True if initialized */ -    unsigned char i, j;            /* State variables */ -    unsigned char s[256];          /* State variables */ -  } prng; - -  /* Initialize the state of the random number generator once, -  ** the first time this routine is called.  The seed value does -  ** not need to contain a lot of randomness since we are not -  ** trying to do secure encryption or anything like that... -  ** -  ** Nothing in this file or anywhere else in SQLite does any kind of -  ** encryption.  The RC4 algorithm is being used as a PRNG (pseudo-random -  ** number generator) not as an encryption device. -  */ -  if( !prng.isInit ){ -    int i; -    char k[256]; -    prng.j = 0; -    prng.i = 0; -    sqliteOsRandomSeed(k); -    for(i=0; i<256; i++){ -      prng.s[i] = i; -    } -    for(i=0; i<256; i++){ -      prng.j += prng.s[i] + k[i]; -      t = prng.s[prng.j]; -      prng.s[prng.j] = prng.s[i]; -      prng.s[i] = t; -    } -    prng.isInit = 1; -  } - -  /* Generate and return single random byte -  */ -  prng.i++; -  t = prng.s[prng.i]; -  prng.j += t; -  prng.s[prng.i] = prng.s[prng.j]; -  prng.s[prng.j] = t; -  t += prng.s[prng.i]; -  return prng.s[t]; -} - -/* -** Return N random bytes. -*/ -void sqliteRandomness(int N, void *pBuf){ -  unsigned char *zBuf = pBuf; -  sqliteOsEnterMutex(); -  while( N-- ){ -    *(zBuf++) = randomByte(); -  } -  sqliteOsLeaveMutex(); -}  | 
